Switched-mode power supplies are commonly used for applications requiring high power conversion efficiency and small footprint. However, switched-mode power supplies tend to be noisier than linear converters.
One solution presented in U.S. Pat. No. 6,765,774 is to provide the switched-mode power supply with a high impedance system for blocking electromagnetic interferences. In this case a switch is used for isolating the power source from interferences produced by the load. However, by doing so the switched-mode power supply loses efficiency through power dissipation.